The NKG2x/CD94 family of C-type lectin-like immunoreceptors (x = A, B, C, E, and H) mediates surveillance of MHC class Ia cell surface expression, often dysregulated during infection or tumorigenesis, by recognizing the MHC class Ib protein HLA-E that specifically presents peptides derived from class Ia leader sequences. In this study, we determine the affinities and interaction thermodynamics between three NKG2x/CD94 receptors (NKG2A, NKG2C, and NKG2E) and complexes of HLA-E with four representative peptides. Inhibitory NKG2A/CD94 and activating NKG2E/CD94 receptors bind HLA-E with indistinguishable affinities, but with significantly higher affinities than the activating NKG2C/CD94 receptor. Despite minor sequence differences, the peptide presented by HLA-E significantly influenced the affinities; HLA-E allelic differences had no effect. These results reveal important constraints on the integration of opposing activating and inhibitory signals driving NK cell effector functions.
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http://dx.doi.org/10.4049/jimmunol.174.5.2878 | DOI Listing |
Cancer Immunol Res
January 2025
Vanderbilt University, Nashville, TN, United States.
Tumor-specific HLA class I expression is required for cytotoxic T-cell elimination of cancer cells expressing tumor-associated or neo-antigens. Cancers downregulate antigen presentation to avoid adaptive immunity. The highly polymorphic nature of the genes encoding these proteins, coupled with quaternary-structure changes after formalin fixation, complicate detection by immunohistochemistry.
View Article and Find Full Text PDFBiomaterials
January 2025
Department of Biomedical Engineering, University of Iowa, Iowa City, IA, 52242, USA; Department of Radiation Oncology, University of Iowa, Iowa City, IA, 52242, USA; Holden Comprehensive Cancer Center, University of Iowa, Iowa City, IA, 52242, USA. Electronic address:
Immune checkpoint inhibitors (ICIs) show limited success in treating pancreatic ductal adenocarcinoma (PDAC), largely due to immune evasion mechanisms, including downregulating expression of major histocompatibility complex class I (MHC-I). Our retrospective analysis demonstrated that smoking - a state of elevated CO exposure - is correlated with increased MHC I expression in pancreatic tumors. Here we tested our hypothesis that introducing exogenous CO augments the anti-cancer effects of immunotherapy.
View Article and Find Full Text PDFInt J Mol Sci
December 2024
Moores Cancer Center, University of California San Diego, San Diego, CA 92037, USA.
The discovery of tumor-derived neoantigens which elicit an immune response through major histocompatibility complex (MHC-I/II) binding has led to significant advancements in immunotherapy. While many neoantigens have been discovered through the identification of non-synonymous mutations, the rate of these is low in some cancers, including head and neck squamous cell carcinoma. Therefore, the identification of neoantigens through additional means, such as aberrant splicing, is necessary.
View Article and Find Full Text PDFPLoS One
January 2025
Foot and Mouth Disease Department, National Veterinary Research Institute, Vom, Plateau State, Nigeria.
The global public health risk posed by Salmonella Kentucky (S. Kentucky) is rising, particularly due to the dissemination of antimicrobial resistance genes in human and animal populations. This serovar, widespread in Africa, has emerged as a notable cause of non-typhoidal gastroenteritis in humans.
View Article and Find Full Text PDFCell Biol Toxicol
January 2025
Department of Medical Oncology, the First Hospital of China Medical University, Shenyang, Liaoning, China.
Background: Microsatellite instability-high (MSI-H) metastatic colorectal cancer (CRC) patients are the dominant population in immune checkpoint blockade treatments, while more than half of them could not benefit from single-agent immunotherapy. We tried to identify the biomarker of MSI-H CRC and explore its role and mechanism in anti-PD-1 treatments. Tumor-specific MHC-II was linked to a better response to anti-PD-1 in MSI-H CRC and CD74 promoted assembly and transport of HLA-DR dimers.
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